This invention relates to the use of certain bridged Group 4 transition metal complexes possessing a unique bridge structure in a gas-phase olefin polymerization catalyst. The unique bridge consists of either boron or aluminum atoms which are further ligated with nitrogen containing groups. The unique bridging structures in the complexes provides for gas-phase olefin polymerization catalysts with exceptionally high catalytic efficiency, and processes giving unique polymer properties.
In Angew. Chem. Int. Ed. Engl., 36, 21, p2338-2340 (1997) and in Phosphorus, Sulfur, and Silicon, 124 & 125, p561-565 (1997) amido substituted boron bridged ferrocenophanes useful for forming poly(ferrocenes) by a ring opening polymerization were disclosed. The synthesis and characterization of Group 1 and 2 metal and tin complexes of 1,2-bis(dimethylamino)-1,2-di-9-fluorenyldiboranes were disclosed in Chem. Ber., 127, p1901-1908, (1994). Diboranes having structure similar to those employed in the foregoing study were disclosed by the same researchers in Eur. J. Inorg. Chem., p505-509 (1998). Ferrocenophane derivatives of similar bisboranes for further molecular property studies were disclosed by J. Organomet. Chem., 530 p117-120 (1997). In Organometallics, 16, p4546-4550 (1997) boron bridged ansa metallocene complexes including dimethylsulifide and phosphine adducts thereof of possible use in Ziegler-Natta-type olefin polymerizations were disclosed.
In the patent literature, bridged metal complexes for use as olefin polymerization catalyst components, including such complexes containing one or more boron atoms in the bridge are generically disclosed by EP-A-416,815 and WO 98/39369.